Matt Cutts has recently posted to his blog that Google is going to now notify webmasters that submit their website xml sitemap to the sitemap program.

It's currently in beta so at the moment, only a random select few are being sent notifications.

I hope this is something that pulls out of beta. I use natural techniques, but some of my clients inadvertantly use black hat techniques when working on their websites themselves. This way we would know if the site is banned, and that we can work on fixing the issues.